(1) Field of the Invention
The present invention relates generally to neural monitoring and, more particularly, to wireless neural data acquisition.
(2) Description of the Prior Art
The use of wireless devices to capture neural data is known in the art. Irazoqui-Pastor et al. in “In-Vivo EEG Recording Using a Wireless Implantable Neural Transceiver,” 1st International IEEE EMBS Conference on Neural Engineering, Capri Island, Italy (Mar. 20-22, 2003) describe recording in-vivo EEG signals using a wireless implantable neural transceiver. This device is inductively powered, does not have selectable gain, digital programmability, or band-pass capability. This device also uses differential input amplifiers, does not use a multiplexer (MUX) and thus it can only record from a single channel. It uses an inefficient voltage-control oscillator (VCO) with a power amplifier, which provides low transmission range and low reliability with large power consumption. This invention also uses a cumbersome and unreliable monopole antenna. Furthermore, this invention does not have a receiver.
Pedram Mohseni and Khalil Najafi in “A Low Power Fully Integrated Bandpass Operational Amplifier for Biomedical Neural Recording Applications,” 24th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Houston, Tex. (Oct. 23-26, 2002) teach a system that uses a single sub-threshold metal oxide semiconductor field-effect transistor (MOSFET) at the input to adjust the RC pole location generated by the capacitance between the recording electrode and the biological tissue. The device was tuned using on-chip resistors which had to be laser-trimmed individually for each chip, which then worked only with the electrode for which it had been trimmed. Additionally the amplifiers experienced significant drift as a result of the manner in which the input was connected.
These prior art inventions have either poor reliability and/or are impractical for large-scale use. Thus, a need exists for a wireless multi-channel neural data acquisition system that is of robust design, low power-consumption, and flexible with tunable bandpass filtering and selectable gain.